Subtracting 10 hours should move to yesterday, but it doesn't

Question

I'm subtracting 10 hours from date object. Expecting to get yesterday's date.

But I get the same date. Is it a bug in ads-script?

  var now = new Date();
  Logger.log("now.getHours() = "+now.getHours());
  var nowDateStr = Utilities.formatDate(now, AdsApp.currentAccount().getTimeZone(),  'yyyy-MM-dd');
  Logger.log("nowDateStr = "+nowDateStr);
  
  var past = new Date(now.getTime() - 10 * 3600 * 1000);
  var pastHour = past.getHours();

  var pastDateStr = Utilities.formatDate(past, AdsApp.currentAccount().getTimeZone(),  'yyyy-MM-dd');
  query = "SELECT customer.id, metrics.impressions, segments.hour FROM customer WHERE metrics.impressions = 0 AND segments.hour = " + pastHour + " AND segments.date = '" + pastDateStr + "'";
  Logger.log("query " + query);

Answer 1

A timezone issue. past.getHours() returns the hour in 'local' time meaning the time zone of the machine running the query, probably UTC or PDT vs pastDateStr is computed with the timezone of the Ads account.

var pastHourStr = Utilities.formatDate(past, AdsApp.currentAccount().getTimeZone(), 'H');